Description Of Function - Graf one2clean+ Instruction For Operation And Maintenance

3. Description of function

3.1 Description of the wastewater treatment process
The one2clean+ wastewater treatment system is a fully biological system and functions on the principle of
the retention process with extended aeration (Sequencing Batch Reactor). The system basically consists
of an aerobic stage, which is split into a rest and an aeration zone, linked together in the lower section.
This process therefore subjects all the domestic wastewater directly to aerobic wastewater treatment.
Blowing in compressed air aerates the entire system and the resultant aerated sludge biologically cleans
the wastewater.
The coarse materials and floating solids in the wastewater are initially retained using a scum guard in the
rest zone. Then the wastewater passes into the aeration zone via an aperture under the scum guard.
The rest zone is aerated too, so the retained solids are also aerobically broken down over the course of
time. In the one2clean+, the wastewater is treated without pre-treatment so no anaerobic putrefaction
processes can occur.
The SBR procedure is a series of different steps, undertaken one after another and at least once a day.
Step 1: Aeration
In the first phase, the wastewater is put straight through aerobic treatment for a fixed
time. As a result, the microorganisms (aerated sludge) are supplied with the oxygen
needed for the breakdown and then pressure aeration causes mixing. The system's
aeration equipment is supplied with ambient air by a compressor. Aeration is intermit-
tent so that targeted wastewater cleaning is possible. Different ambient conditions can
thereby be achieved.
Step 2: Settle
There is no aeration in the second phase. The aerated sludge and the remaining settle-
able solids can now settle with the aid of gravity. A clear water zone forms at the top
and a sludge layer at the bottom. Any floating sludge is on top of the clear water zone.
Step 3: Clear water extraction
In this phase, the biologically cleaned wastewater (clear water) is drawn out of the SBR
stage. It is pumped out by an air lift (or mammoth) pump, which uses compressed air.
The air lift pump is designed not to pump out any floating sludge on top of the clear
water layer. A minimum water level is maintained in the system without any further
components.
In multi-tank systems, there is also a phase in which the sludge is returned to the system.
Once step is complete, the cleaning process starts again with step 1.
Two cycles are undertaken a day. The maintenance company can individually adapt the switching times.
3. Description of function
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